package com.xhui.vimarket.common.utils.collection;

import java.util.Set;
import java.util.TreeSet;

public class SetUtil {
    //并集
    public static <T> Set<T> union(Set<T> setA, Set<T> setB) {
        Set<T> tmp = new TreeSet<T>(setA);
        tmp.addAll(setB);
        return tmp;
    }
    
    //交集
    public static <T> Set<T> intersection(Set<T> setA, Set<T> setB) {
        Set<T> tmp = new TreeSet<T>();
        for (T x : setA)
            if (setB.contains(x))
                tmp.add(x);
        return tmp;
    }
    
    //差集
    public static <T> Set<T> difference(Set<T> setA, Set<T> setB) {
        Set<T> tmp = new TreeSet<T>(setA);
        tmp.removeAll(setB);
        return tmp;
    }
    
    //全差集
    public static <T> Set<T> symDifference(Set<T> setA, Set<T> setB) {
        Set<T> tmpA;
        Set<T> tmpB;
        
        tmpA = union(setA, setB);
        tmpB = intersection(setA, setB);
        return difference(tmpA, tmpB);
    }
    
    //子集合判斷
    public static <T> boolean isSubset(Set<T> setA, Set<T> setB) {
        return setB.containsAll(setA);
    }
    
    //父集合判斷
    public static <T> boolean isSuperset(Set<T> setA, Set<T> setB) {
        return setA.containsAll(setB);
    }
    
    public static void main(String args[]) {
        TreeSet<Character> set1 = new TreeSet<Character>();
        TreeSet<Character> set2 = new TreeSet<Character>();
        
        set1.add('A');
        set1.add('B');
        set1.add('C');
        set1.add('D');
        
        set2.add('C');
        set2.add('D');
        set2.add('E');
        set2.add('F');
        
        System.out.println("set1: " + set1);
        System.out.println("set2: " + set2);
        
        System.out.println("Union: " + union(set1, set2));
        System.out.println("Intersection: " + intersection(set1, set2));
        System.out.println("Difference (set1 - set2): " + difference(set1, set2));
        System.out.println("Symmetric Difference: " + symDifference(set1, set2));
        
        TreeSet<Character> set3 = new TreeSet<Character>(set1);
        
        set3.remove('D');
        System.out.println("set3: " + set3);
        
        System.out.println("Is set1 a subset of set2? " + isSubset(set1, set3));
        System.out.println("Is set1 a superset of set2? " + isSuperset(set1, set3));
        System.out.println("Is set3 a subset of set1? " + isSubset(set3, set1));
        System.out.println("Is set3 a superset of set1? " + isSuperset(set3, set1));
        
    }
}
